Fix string/gid collision in job arguments

Serialize Global IDs as special objects, distinguishable from Strings

activejob/lib/active_job/arguments.rb

@@ -35,12 +35,15 @@ def deserialize(arguments)
     end
 
     private
+      GLOBALID_KEY = '_aj_globalid'.freeze
+      private_constant :GLOBALID_KEY
+
       def serialize_argument(argument)
         case argument
         when *TYPE_WHITELIST
           argument
         when GlobalID::Identification
-          argument.to_global_id.to_s
+          { GLOBALID_KEY => argument.to_global_id.to_s }
         when Array
           argument.map { |arg| serialize_argument(arg) }
         when Hash
@@ -61,16 +64,37 @@ def deserialize_argument(argument)
         when Array
           argument.map { |arg| deserialize_argument(arg) }
         when Hash
-          argument.each_with_object({}.with_indifferent_access) do |(key, value), hash|
-            hash[key] = deserialize_argument(value)
+          if serialized_global_id?(argument)
+            deserialize_global_id argument
+          else
+            deserialize_hash argument
           end
         else
           raise ArgumentError, "Can only deserialize primitive arguments: #{argument.inspect}"
         end
       end
 
+      def serialized_global_id?(hash)
+        hash.size == 1 and hash.include?(GLOBALID_KEY)
+      end
+
+      def deserialize_global_id(hash)
+        GlobalID::Locator.locate hash[GLOBALID_KEY]
+      end
+
+      def deserialize_hash(serialized_hash)
+        serialized_hash.each_with_object({}.with_indifferent_access) do |(key, value), hash|
+          hash[key] = deserialize_argument(value)
+        end
+      end
+
+      RESERVED_KEYS = [GLOBALID_KEY, GLOBALID_KEY.to_sym]
+      private_constant :RESERVED_KEYS
+
       def serialize_hash_key(key)
         case key
+        when *RESERVED_KEYS
+          raise SerializationError.new("Can't serialize a Hash with reserved key #{key.inspect}")
         when String, Symbol
           key.to_s
         else

activejob/test/cases/argument_serialization_test.rb

@@ -31,12 +31,12 @@ class ArgumentSerializationTest < ActiveSupport::TestCase
   end
 
   test 'should convert records to Global IDs' do
-    assert_arguments_roundtrip [@person], [@person.to_gid.to_s]
+    assert_arguments_roundtrip [@person], ['_aj_globalid' => @person.to_gid.to_s]
   end
 
   test 'should dive deep into arrays and hashes' do
-    assert_arguments_roundtrip [3, [@person]], [3, [@person.to_gid.to_s]]
-    assert_arguments_roundtrip [{ 'a' => @person }], [{ 'a' => @person.to_gid.to_s }.with_indifferent_access]
+    assert_arguments_roundtrip [3, [@person]], [3, ['_aj_globalid' => @person.to_gid.to_s]]
+    assert_arguments_roundtrip [{ 'a' => @person }], [{ 'a' => { '_aj_globalid' => @person.to_gid.to_s }}.with_indifferent_access]
   end
 
   test 'should stringify symbol hash keys' do
@@ -51,6 +51,14 @@ class ArgumentSerializationTest < ActiveSupport::TestCase
     assert_raises ActiveJob::SerializationError do
       ActiveJob::Arguments.serialize [ { :a => [{ 2 => 3 }] } ]
     end
+
+    assert_raises ActiveJob::SerializationError do
+      ActiveJob::Arguments.serialize [ '_aj_globalid' => 1 ]
+    end
+
+    assert_raises ActiveJob::SerializationError do
+      ActiveJob::Arguments.serialize [ :_aj_globalid => 1 ]
+    end
   end
 
   test 'should not allow non-primitive objects' do